Body weight following a multidomain lifestyle intervention in older adults at risk of dementia – A post-hoc analysis of the AgeWell.de-trial

Background: Lifestyle interventions provide a promising approach to address higher body weight as a risk factor for dementia. Objective: The AgeWell.de-trial was primarily designed to preserve cognitive function and reduce dementia risk. In this post-hoc analysis, we investigated body weight following the multidomain intervention among older adults with overweight or obesity, as well as the role of motivation and confidence regarding weight loss. Methods: Analyses used data from the cluster-randomized AgeWell.de-trial, testing a multidomain intervention (dietary counselling, enhancement of physical, social and cognitive activity, medication review, intervention for cardiovascular risk factors, depressive symptoms/grief, if applicable) over 24 months in adults aged 60 to 77 years at risk for dementia. Associations between intervention allocation and body weight at follow-up were analyzed using linear regression, controlling for covariates, based on multiply imputed data. Results: The sample included n = 678 participants with a BMI ≥ 25 kg/m², mean age (SD): 68.9 (4.8), 52.1% female. Group allocation was not associated with body weight at 24-month follow-up (b (unstandardized regression coefficient) = -0.30, 95% CI: -0.51; 1.11). Older age (b = -0.14, 95% CI: -0.25; -0.03) and a high level of education (b = -1.28, 95% CI: -2.55; 0.00) were linked to lower body weight at follow-up, while higher baseline body weight predicted higher body weight at follow-up (b = 0.95, 95% CI: 0.91; 0.98). Levels of motivation and confidence regarding weight loss remained high but stable in both groups, regardless of group allocation. Conclusions: In this post-hoc analysis, group allocation was not associated with lower body weight at follow-up. Despite high levels of motivation and confidence regarding weight loss and favorable changes in diet and physical activity in the intervention group, these changes did not translate into measurable weight loss. Trial registration: AgeWell.de was prospectively registered in the German Clinical Trials Register on December 7th, 2017 (DRKS trial identifier DRKS00013555).